三维内镜超声体积测量准确性的评估

Accuracy of Volume Measurement by Three-dimensional Endoscopic Ultrasonography

背景:常规内镜超声(EUS)应用于消化道疾病的诊断已有相当时日,但其仅能提供平面图像,而新型三维EUS(3D-EUS)能对病变进行三维成像和体积测量。目的:探索3D-EUS的三维成像技术及其体积测量功能的可行性和准确性。方法:采用3D-EUS对不同明胶模型进行体积测量并与其实际体积相比较,从而得出其准确率。对2ml针筒(直径10mm)制作的1000mm3模型分别在横断面图像间距设为0.25mm、0.35mm、0.5mm、0.75mm和1mm时测量其体积。其中,在横断面图像间距设为1mm时,另将探头与模型之间的距离设为0mm、5mm和10mm,探头与模型之间的角度设为0°、10°和20°,以及设置不同测量面积间隔,分别测量每种条件下的模型体积,并与其实际体积相比较,以及与5ml针筒(直径14mm)制作的1000mm3模型相比较。对2ml针筒制作的500mm3、1000mm3、1500mm3和2000mm3模型以及1000mm3BorrmannⅠ型、Ⅱ型、Ⅲ型胃癌模型,在横断面图像间距设为1mm时测量其体积并与其实际体积相比较。结果:3D-EUS对1000mm3柱状体明胶模型和胃癌模型体积测量的准确率分别为99.0%±0.9%和99.0%±1.3%。探头与目标物之间距离太近或太远、角度过大、测量面积间隔过大、目标物直径过大、体积过小等因素均会导致测量结果误差增大。当距离设为5mm、角度设为0°、测量面积间隔<4mm、目标物直径在10mm、体积>1000mm3时,测得的结果最为准确。结论:3D-EUS能对胃肠道病变进行三维成像,在模拟病变的体积测量中显示出很高的准确性,对今后临床肿瘤的诊治具有很高的实用价值。

Background： Conventional endoscopic uhrasonography （EUS） has been used for the diagnosis of digestive tract diseases for a long time, but it can only provide plane imaging. The new three-dimensional EUS （3D-EUS） can provide three-dimensional imaging and be used for volume measurement. Aims： To investigate the feasibility of three-dimensional imaging and accuracy of volume measurement with 3D-EUS. Methods： The volume of different gelatin models was measured with 3D-EUS, and the accuracy was evaluated by comparing it with the actual volume. Firstly, the 1000 mm^3 model made by 2 ml syringe （diameter 10 mm） was scanned at pitches of 0.25 mm, 0.35 mm, 0.5 mm, 0.75 mm and 1 mm. It was also measured at a pitch of 1 mm and setting the probe distance at 0 mm, 5 mm and 10 mm, the probe angle at 0°, 10° and 20°, and at different area measurement intervals, and compared it with similar volume model made by 5 ml syringe （1000 mm^3, diameter 14 mm） and actual volume. Then the gelatin models of 500 mm^3, 1000 mm^3, 1500 mm^3 and 2000 mm^3 made by 2 ml syringe and 1000 mm^3 models of Borrmann type Ⅰ, Ⅱ, Ⅲ gastric cancer were measured at a pitch of 1 mm and compared it with the actual volume. Results： For the measured volume of 1000 mm^3 gelatin model and gastric cancer model, we found an accuracy reaching 99.0%±0.9% and 99.0%±1.3%, respectively. With too great or too less probe distance, too great probe angle, too great area measurement interval, too great diameter and too less size of the target subject, it could lead to greater degree of error. It was most accurate when the probe distance was set at 5 mm, the probe angle at 0°, the area measurement interval 〈4 mm, the diameter around 10 mm and the volume of target subject 〉1000 mm^3. Conclusions： 3D-EUS can provide three-dimensional imaging of gastrointestinal lesions and has a high accuracy in measuring the volume of models of gastrointestinal lesions, therefore, it is valuable for tumor diagnosis and treatment.